case 1

Worksheet 6, Clip 1, Discussion of Question 1, 3:20

In this clip the teacher introduces inverse trig functions.

Worksheet 6, Clip 2, Discussion of Question 2, 2:35

In this clip the teacher leads a discussion about how the problem should be approached now the radius is not 1.

Worksheet 6, Clip 3, Discussion of Question 3, Part I, 1:23

In this clip the teacher initiates a discussion about the input for the inverse trig functions.

Worksheet 6, Clip 4, Discussion of Question 3, Part II, 4:14

In this clip the teacher leads a discussion about why arccos and arcsin gave different results.

Worksheet 6, Clip 4, Discussion of Question 3, Part II, 4:14

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  • Notice that the teacher is explicit about what the input and output are for the inverse trig functions. Also, the teacher is writing the output as being divided by the radius, in this case 2.5. This will help reinforce this relationship.
  • The goal is to have students see that arcsin and arccos may give different arclengths. Thus the students need to be made aware which arclength they are calculating. He uses this opportunity to discuss what the output is of each particular function. This is a useful way to motivate the need for reference angles.
  • In this case the teacher had a student explain why this happened, but if necessary a teacher led discussion would also work. The teacher does a nice job of reinforcing what the student said and using the diagram to show the relationship between the two points (that they have the same vertical height from the horizontal axis).